The UN on Tuesday accused Israel of using starvation as a "weapon of war", saying this could be a "war crime".
"The situation of hunger, starvation and famine is a result of Israel's extensive restrictions on the entry and distribution of humanitarian aid and commercial goods," United Nations Human Rights Commissioner Volker Turk said.
Earlier on Tuesday, explosions and shootings shook the Gaza Strip’s biggest hospital and surrounding neighbourhoods as Israeli forces stormed through the facility.
At least 50 people were killed there on Monday by Israeli forces.
The raid was a new attack on the Shifa medical complex, which had only partially resumed operations after a destructive Israeli raid in November.
Thousands of Palestinian patients, medical staff and displaced people were trapped inside the sprawling complex Tuesday as heavy fighting between troops and Hamas fighters raged in nearby districts.
Details were scarce, with communications from inside the hospital nearly impossible.